Blackbird v. Mig-25

"Venik" wrote in message
...
Wolfhenson wrote:

Any steel
containing 5% nickel or more is considered to be resistant to
atmospheric corrosion in addition most nickel steels contain chromium
in similar quantity as nickel and that is another element that makes
the steel stainless.

Let's stick to technical definitions: stainless steel is a ferrous alloy
with a minimum of 10.5% chromium content. Major elements of the MiG-25
were made of appoximately 80% of VNS-2, VNS-4, and VNS-5 alloys, 11% D-19T
aluminum alloy and 8% OT4-1 titanium alloy, none of which falls under this
definition.

Really? Ah, there goes one of my favourite aviation anecdotes.



John

On Sun, 12 Sep 2004 02:13:50 +0100, "John Mullen"
wrote:

"Venik" wrote in message
...
Wolfhenson wrote:

Any steel
containing 5% nickel or more is considered to be resistant to
atmospheric corrosion in addition most nickel steels contain chromium
in similar quantity as nickel and that is another element that makes
the steel stainless.

Let's stick to technical definitions: stainless steel is a ferrous alloy
with a minimum of 10.5% chromium content. Major elements of the MiG-25
were made of appoximately 80% of VNS-2, VNS-4, and VNS-5 alloys, 11% D-19T
aluminum alloy and 8% OT4-1 titanium alloy, none of which falls under this
definition.

Really? Ah, there goes one of my favourite aviation anecdotes.



John



I'd always wondered if it was made of cast iron and we were giving
them too much credit.

"John Mullen" wrote in message ..

Really? Ah, there goes one of my favourite aviation anecdotes.
.....
John

Sir,
I am happy to inform You that Your favourite aviation anecdote is
still very much alive. This is how www.aeronautics.ru describes that
same steel in an article about Su-29 aerobatics plane
quote : "...fuselage has basic welded truss structure of VNS-2
high-strength stainless steel tubing;...
www.aeronautics.ru/archive/vvs/su29-01.htm "end quote
And some more quotes :
"...high-strength stainless steel VNS-2 that corresponds in
composition to the steel 08Kh15N5D2T (08Cr15Ni5Cu2Ti). ...
http://www.kluweronline.com/article....S=495948&PDF=1 "

"The choice of the materials was also dependent on the performances -
up to 80% of the plane was made up of VNS-2, VNS-4 and VNS-5 stainless
steel, about 8% was ...
http://www.testpilot.ru/russia/mikoy...25/mig25_e.htm "

And for the record stainless steel is kind of steel that is resistant
to atmospheric corrosion(it will not rust that is) regardless of it's
composition and if chromium is the only element added then the
required content would be 12% or higher.

Nemanja Vukicevic
aeronautical engineering student

"Wolfhenson" wrote in message
om...
"John Mullen" wrote in message
..

Really? Ah, there goes one of my favourite aviation anecdotes.
....
John

Sir,
I am happy to inform You that Your favourite aviation anecdote is
still very much alive. This is how www.aeronautics.ru describes that
same steel in an article about Su-29 aerobatics plane
quote : "...fuselage has basic welded truss structure of VNS-2
high-strength stainless steel tubing;...
www.aeronautics.ru/archive/vvs/su29-01.htm "end quote
And some more quotes :
"...high-strength stainless steel VNS-2 that corresponds in
composition to the steel 08Kh15N5D2T (08Cr15Ni5Cu2Ti). ...
http://www.kluweronline.com/article....S=495948&PDF=1 "

"The choice of the materials was also dependent on the performances -
up to 80% of the plane was made up of VNS-2, VNS-4 and VNS-5 stainless
steel, about 8% was ...
http://www.testpilot.ru/russia/mikoy...25/mig25_e.htm "

And for the record stainless steel is kind of steel that is resistant
to atmospheric corrosion(it will not rust that is) regardless of it's
composition and if chromium is the only element added then the
required content would be 12% or higher.

Thank you, that's very interesting and makes perfect sense.

John

Venik wrote in message ...
Wolfhenson wrote:

Any steel
containing 5% nickel or more is considered to be resistant to
atmospheric corrosion in addition most nickel steels contain chromium
in similar quantity as nickel and that is another element that makes
the steel stainless.

Let's stick to technical definitions: stainless steel is a ferrous alloy
with a minimum of 10.5% chromium content. Major elements of the MiG-25
were made of appoximately 80% of VNS-2, VNS-4, and VNS-5 alloys, 11%
D-19T aluminum alloy and 8% OT4-1 titanium alloy, none of which falls
under this definition.

The steels used by Russian aircraft makers would probably be more
correctly described as corrosion resistant austinitic steels.
Stainless Steel AFAIKS is only one type of austinitic steel.

Steel, Titanium, Aluminium all have approximetly the same tensile
strength per unit weight. Aluminium being less dense than steel is
weaker for the same cross sectional area and more must be used. For
some structures of an aircraft that are under compressive forces the
thicker guages of Aluminium used provides superior stiffness and
resistence to buckling although tensile strength is the same.

Steel is a perfectly good material for highly concentrated stressed
components such as the wing, spars and tail. In these areas Aluminium
looses its advantage. Aluminium is good for Most parts of the
fueselage where stresses are less concentrated.

Titanium falls in between Aluminium and Steel in Density and Heat
resistence.

Steel has superior thermal resistence than Titanium and Titanium
better than Aluminium. The use of corrosion resitent steels on many
parts of Russian aircraft may have more to do with resistence to
atmopsheric corrosion due to moisture than that due to high
temperature oxidation.

Steel most defintely is not an inferior material to Titanium: in many
cases it is superior in physical properties. It all depends on what
the objective is.